char * mergeAlternately(char * word1, char * word2)
{   
    int i=0;
    int len1=strlen(word1);
    int len2=strlen(word2);
    char *res= (char*)malloc(sizeof(char)*(len1+len2+1));
    int j=0;int k=0;
    while(i<len1+len2)
    {
        if(word1[j]!='\0')
        {   
            res[i]=word1[j];
            j++;
            i++;
        }
        if(word2[k]!='\0')
        {   
            res[i]=word2[k];
            k++;
            i++;
        }
    }
    res[len1+len2]='\0';
    return res;
}